1. Field of the Invention
The present invention relates to the use of lectins for the treatment of skin disorders associated with hyperproliferation of keratinocytes or with hyperkeratosis, particularly, but not exclusively, psoriasis and benign keratoses. Lectins are plant or animal proteins or glycoproteins of non-immune origin with specific affinity for carbohydrates.
2. Description of the Related Art
Lectins have been used widely as probes for locating carbohydrate groups in cell membranes, since they have affinities for certain saccharides.
Certain lectins are known to act as mitogens, i.e. stimulators of cell proliferation. For example, peanut agglutinin (PNA) is a mitogen for human colon epithelial cells [S. D. Ryder et al., J. Nat. Cancer Institute 84, 1410-1416 (1992)]. Conconavalin A (Con-A) and phyto-hemagglutinin have a mitogenic effect on haematopoietic cells.
On the other hand, certain lectins have been reported to have an anti-tumour action. See, for example, Japanese Patent Application Publication (Kokai) No. 61-205218, (Ajinomoto K. K.), published in 1986, which mentions the agglutinins of a) Agaricus bisporus, b) Trichosanthes kinlowii, c) Rhizobium trifolii, d) Salvia horminium, e) Maclura pomifera, f) Sarothamnus scoparius, g) Wistaria floribunda, h) Griffonia (Bandeiraea) simplicifolia and i) Euonymus europeus.